WASHINGTON: United States(US) lawmakers demanded to know on Monday why President Barack Obama was not informed for several months that his CIA chief David Petraeus was under investigation in an explosive sex scandal.

Friend3 Name:Email:Anti-Spam *Type this CASE SENSITIVE anti-spam security code into the field below

Petraeus resigned on Friday after confessing to an extramarital affair, stunning Washington political and intelligence circles just three days after Obama's re-election and amid a probe into US security failings in Libya.

It is reported that top FBI and Justice Department figures learned of the scandal late last summer, but decided to leave both the White House and the congressional committees that oversee their work in the dark until last week.Key members of Congress demanded a fuller explanation of a liaison that could have involved a national security breach, arguing that hiding the investigation showed poor judgment by the FBI and senior Obama administration officials at the Justice Department.

"This is certainly an operationally sensitive matter," said Senator Dianne Feinstein, Democratic chair of the Senate Intelligence Committee. "But we weren't briefed. I don't know who made that decision. "So it is very puzzling and I think was a mistake, because this thing just came so fast and so hard. And since then, it's been like peeling an onion. Every day, another peel comes off," she told MSNBC.

It is unclear exactly when FBI Director, Robert Mueller and Attorney General Eric Holder were informed although it has emerged that the investigation began as early as May. "This is a crisis, I believe, of major proportions," declared Peter King, the Republican chair of the Homeland Security Committee.

"It's not the usual political thing. We're not talking about the secretary of commerce or some undersecretary somewhere. We're talking about the heads of the FBI," he said. King argued that the case "had to be brought to the president, or certainly to the National Security Council. If not, the FBI was derelict in its duty. "I don't want to raise any conspiracy theories, but I certainly have questions," he added.

Petraeus had been due to testify Thursday at closed door congressional inquiries into the deadly September 11 attack on the US consulate in Benghazi, Libya, but will now be replaced by acting CIA Director Michael Morell. The scandal shocked friends and allies of the retired general, the most celebrated officer of his generation, who commanded the US campaign in Iraq and Afghanistan before taking charge of the CIA 14 months ago.

He admitted to the extramarital affair in a resignation message to the CIA workforce on Friday, calling the lapse of judgment "unacceptable" for a husband and leader. He has been married to his wife Holly for 38

years. Obama learned of the scandal two days after Tuesday's US election, according to the White House, and accepted the resignation the following day.

In the US military, adultery can be considered a crime. As CIA director, Petraeus was a civilian but the potential security breach could have left him open to blackmail or undermined his credibility with his staff. Steven Boylan, a retired army colonel and former Petraeus spokesman, said his former boss told him over the weekend that the affair with his biographer, Paula Broadwell, began about two months after he became CIA director and ended four months ago.

"He is devastated, you could say, and you could also say that it's going to take a long time for the family or sometime for the family to get through this, but they will," Boylan told NBC. It all unraveled when a Tampa woman went to the FBI in the early summer after she began receiving threatening emails accusing her of a flirtation with the general, the Washington Post said.

A government official told The New York Post that the emails contained such language as: "I know what you did," "back off" and "stay away from my guy." US media identified the Tampa woman as 37-year-old Jill Kelley, a "social liaison" to an air force base in who had a longstanding family friendship with Petraeus but no official status in the military.

The FBI soon traced the emails to Broadwell, a 40-year-old former army major and mother of two who had been given unprecedented access to his command in Afghanistan in 2011 in order to write her glowing biography. The agents eventually discovered sexually explicit emails between Petraeus and Broadwell indicating the affair. The pair were interviewed separately by investigators in late October and early November.

Broadwell was found to be in possession of some classified material, but Petraeus was cleared of involvement and no criminal charges have been forthcoming. The scandal has left Obama with a hole to fill on his national security team at a time when he is also expected to be replacing his secretaries of state, defense and treasury.

One name being floated as a possible Petraeus replacement is John Brennan, the White House counter-terrorism adviser and a CIA veteran who has played an instrumental role in Obama's drone war against al Qaeda militants.Others say Morell, the acting director, may take on the role permanently. (Sapa-AFP)